(P5 - Snow Leopard - Windows 7) Mouse Scroll Wheel Stopped Working! =/

I'm not sure what's changed, but my mouse scroll wheel functionality has stopped working. I've tried restoring the Windows 7 install, no go. I tried reinstalling Parallels Tools, no go.

I have noticed that there is now a PS/2 Mouse Driver installed and configured as the primary mouse... but I'm not sure if this was there before the issue started or if it's a potential cause.

I haven't updated my Parallells 5 after migrating to Snow Leopard, that might also be a cause. However, I am not interested in updating my version of Parallels at this time. So hopefully, that's not the solution.

Thanks to everyone at the Parallels Team for building a kick-ass piece of software, and to all who help answer this anomaly!

~John
Brooklyn, NY